The present invention relates to a device for removing occlusions from a biological vessel. Specific embodiments of the present invention relate to a catheter for dislodging and collecting thrombus material from arteries and in particular brain arteries without compromising the integrity of the thrombus mass.
The rapid and effective treatment of an ischemic stroke is a key factor in minimizing the morbidity and mortality that may otherwise result from this medical emergency. In Ischemic stroke, thrombotic material causes occlusion of the arterial vessels that supply blood to the brain. In general, the removal of these thrombi from an occluded or partly occluded vessel may be attempted by enzymatically disintegrating the thrombus material via agents such as tissue plasminogen activator (tPA) or alteplase (thrombolysis) by administering, or by mechanically removing the thrombus (thrombectomy).
Three general approaches are utilized for mechanically removing thrombus material from a small blood vessel: a distal approach, a medial approach and a proximal approach.
In the distal approach, the distal end of the retrieval device (typically fitted with a distal basket or snare) is passed through the occlusion and positioned at a distal side thereof. The device is then pulled back (in a proximal direction) while the distal end engages the thrombus material. One example of a commercially-available device employing this approach is the Merci retriever, manufactured by Concentric Medical Inc. and described in U.S. Pat. No. 6,663,650.
In the proximal approach, the distal end of the retrieval device (fitted with a grasper or an aspirator) is brought into contact with the proximal side of the thrombus and the thrombus is then pulled proximally through the vasculature and finally removed from the body. One example of a device utilizing the proximal approach is the Penumbra device, manufactured by Penumbra Inc. and disclosed in EP 1799128.
The medial approach is more commonly used and involves opening a stent-like retrieval device inside the thrombus, compressing the thrombus material against the arterial wall and retrieving the device along with the compressed thrombus material.
Although these approaches can be used to at least partially remove thrombus material occluding an artery, such removal can oftentimes be associated with an increased risk of distal emboli and the release of thrombotic debris. In addition, contact of the device with the endovascular wall, especially in the case of stent-like devices can cause trauma to the vascular tissues as well as precipitate vasospasm.
As such, it would be highly advantageous to have an occlusion removal device capable of removing occlusive material from a biological vessel such as a blood vessel while being devoid of the above limitations.